Prqf^ Ehrenherg's Researches on the Infusoria. 101 



r Musculus lateralis dexter posterior. 



s Portion of the musculus lateralis sinister posterior. 



t Musculus ventralis anterior. 



w Musculus ventralis posterior. 



V Ovaria. 



* Male seminal organs, testes. 



« Nervous circle in the neck. 



fi Cervical ganglion. 



y Recurrent nerves. 



I Great oesophageal ganglion ; above oesophagus. 



( (Esophageal ganglia ; on sides of oesophagus. 



^ Ventral nerve. 



71 Great dorsal vessel. 



4 Transverse twigs, given off from the dorsal vesseL 



N. B The foreign bodies which are seen in the cavity of the intes- 

 tine are individuals of the Naviculafulva and N. gracilit, which 

 the animal has swallowed, and with which the digestive cavity is 

 sometimes completely filled. 

 Fig. 7« Generative organs in their unimpregnated state ; and, 

 Fig. 8. The same organs impregnated. In these two figures, 

 / Represents the testes, or male seminal organs. 

 o V The ovaria. 



« The extremity of the intestine. 

 c I The cloaca communis. 



sph A muscular-looking body, embracing the cloaca,— sphincter ? 

 t» Singularly contractile body, into which are inserted the openings of the 

 testes (vasa deferentia ?) and which not improbably performs the fiinc- 

 tion of a musculus ejaculatorius. 

 Fig. 9. Appearance of the mouth, with its mandibules or teeth, when sepa- 

 rated from the body by pressure between two fine laminae of mica, 

 along with the bulb of the oesophagus. 



Jddendum. 



A remarkable deviation from the normal structure of the 

 male generative organs among the Inf. Rotatoria characterizes 

 the Rotifer vulgaris, Schrank, and the Philodina erythroph^ 

 thalma, Ehrenberg. They are unprovided with the singularly 

 contractile organ which usually embraces the excretory ducts of 

 the male testes, and which is very distinct in the Hydaiina. 

 Its place seems to be supplied by an erectile organ, resembhng 

 very much in form the penis of the higher animals, and which 

 projects from the neck. That this is its nature is rendered very 

 probable from the animal frequently inflecting itself nearly 

 double, and applying this organ to the cloacal orifice situated 



